Enhanced photo-bioelectrochemical energy conversion by genetically engineered cyanobacteria

Area of Science:

• Bioenergetics
• Microbiology
• Biotechnology

Background:

• Photosynthetic microorganisms are explored for energy conversion in photo-bioelectrochemical cells (PBEC).
• Cyanobacteria exhibit light-dependent electrogenic properties, generating photocurrents, but at lower densities than photovoltaics.
• Previous studies showed Nostoc sp. in PBEC generated up to 35 mW m(-2).

Purpose of the Study:

• To genetically engineer cyanobacteria for enhanced extracellular electron transfer.
• To improve photocurrent generation in photosynthetic microbial fuel cells.

Main Methods:

• Genetically engineered Synechococcus elongatus PCC 7942 to express the non-native outer membrane cytochrome S (OmcS).
• Utilized photo-bioelectrochemical cells (PBEC) to measure photocurrent generation.
• Compared engineered S. elongatus with wild-type cyanobacteria.

Main Results:

• Engineered S. elongatus demonstrated significantly higher extracellular electron transfer ability.
• Photocurrent generation on the PBEC anode was approximately ninefold higher compared to wild-type cyanobacteria.
• Successful expression of OmcS in S. elongatus enhanced its electrogenic performance.

Conclusions:

• Genetic engineering of cyanobacteria by introducing OmcS is a viable strategy to boost photocurrent generation.
• This approach holds promise for accelerating the advancement of photosynthetic microbial fuel cell technology.
• Enhanced extracellular electron transfer in cyanobacteria can significantly improve bioelectrochemical energy conversion efficiency.